A flagrancy court on Thursday sentenced four gold miners to three months in prison for extracting gold inside Costa Rica’s treasured Corcovado National Park, in the southern Pacific region.

Park rangers and National Police officers arrested the men on June 20 while they were extracting gold from a river within the limits of the national park, located on the Osa Peninsula.

“The gold mining activities of these persons had an impact on the water clarity up to 1.5 kilometers. They also removed some 20 cubic meters of sediment from the river,” park ranger Tony Salas said last Friday.

The ruling was the first issued by the flagrancy court in the Southern Zone after a resolution of Costa Rica’s Supreme Court authorized them to rule on environmental crimes committed in the cantons of Golfito, Osa and Coto Brus. In Costa Rica, a flagrancy court allows judges to convict suspects within 24 hours of being caught in the act of committing a crime.

According to Carlos Madriz, chief of control and protection at the Osa Conservation Area (ACOSA), environmental damage caused by the gold miners totaled some ₡5 million ($10,000), as they damaged water resources in the area’s ecosystem.

“This ruling helps control continous environmental damage in Corcovado National Park because illegal gold mining keeps affecting valuable ecosystems within protected areas,” ACOSA said in a press release on Thursday.